What happened
On May 18, 2018, a Cessna 310H, registration OB-2004, was conducting a flight training mission from Pisco International Airport to Nazca. The aircraft was operated by a flight school and was occupied by a flight instructor, a student pilot, and a student observer.
During the landing phase at Nazca's Maria Reiche Neuman Airport, the aircraft touched down on runway 25. While taxiing toward taxiway "C," the right main landing gear suddenly collapsed and retracted. This caused the aircraft to lose directional control and veer off the right side of the runway. The aircraft traveled approximately 80 meters off the paved surface, resulting in a propeller strike as the right wing and engine made contact with the ground. The crew successfully executed emergency shutdown procedures to prevent a fire and evacuated the aircraft without injury to the three occupants.
The investigation
The investigation focused on the mechanical failure of the landing gear assembly. Investigators examined the aircraft's maintenance records, noting that a 100-hour inspection had been completed two days prior to the incident with no discrepancies found in the landing gear system.
Technical analysis of the wreckage revealed a fracture in the attachment lug of the bellcrank pin coupling. Fractographic analysis performed by a specialized maintenance organization indicated that the failure of the bellcrank pin coupling lug and the deformation of the pin alojamiento holes in the end fitting side brace lock were caused by excessive bending, tension, and compression stresses. These stresses likely occurred during landing, potentially due to an improper landing technique or operations on uneven runway surfaces.
Findings
- The primary cause of the incident was the collapse of the right main landing gear due to the fracture of the bellcrank pin coupling attachment lug.
- The fracture was the result of excessive mechanical stresses (bending, tension, and compression) sustained during landing.
- Contributing factors included the potential for landing on irregular or uneven surfaces that generate vibration and stress on landing gear components.
- The nature of flight training, which involves frequent takeoffs and landings by student pilots, may subject the aircraft to harder or less precise landings.